var prev='pic0';

function toggle_block(id)
{
    var el = document.getElementById(id);

    if (el.style.display != 'block') el.style.display = 'block';
    else                             el.style.display = 'none';
            
    return false;
}


function enable_block(id)
{
    var el = document.getElementById(id);
    el.style.display = 'block';
    return false;
}

function disable_block(id)
{
    var el = document.getElementById(id);
    el.style.display = 'none';
    return false;
}

function switch_block(id)
{
    if (prev==id) return false;
    
    document.getElementById(id).style.display = 'block';
    document.getElementById(prev).style.display = 'none';
    
    prev = id;
                
    return false;
}